Your buffer here is meat. Cattle are tremendously inefficient consumers of grain. Eat your burgers in the bountiful years, then slaughter 75% of the herd in a hardship year, eat well for six months, then spend the next three, four, five years eating more grains while the herds recover.

Ethanol is another one.

That's the sensible way to do it.

Somehow I doubt that it's the way we do it... But maybe the variability is coming from world trade and developing nations.